Set Instant Pot to sauté, add oil and wait until pot is hot. Season short ribs with salt and pepper. Brown in batches until seared all on sides. Be mindful not to overcrowd the pot, you want to sear not steam the beef. When browned, remove from pan and set in bowl on the side.
Now that the beef is all nicely seared and set aside, add mushrooms to Instant Pot and brown until nicely golden. Remove from pot and place in bowl with the beef.
Time to sauté our onions, carrots and celery. 5 minutes, then we are going to add the potatoes and continue to sauté 3 minutes. Remove all vegetables from put and add to the beef, and mushrooms.
Now we get to make our roux and deglaze the pot, we want all those brown bits of flavor. Add butter to the pot and scrape bottom of pot as butter melts. Add flour and whisk until blended, whisk 3 minutes so all that flour flavor cooks out.
Add two heaping tablespoons of Better than bouillon to the roux and whisk until smooth.
Slowly, pour in wine while continuing to whisk.
Pour in beef stock and whisk to combine roux mixture with stock.
8. Time to put everything back into the pot, making sure you add the juices that collected in the bowl. Add frozen peas, chopped herbs, bay leaf and salt and pepper to taste.
Place lid on Instant Pot, manual 35 minutes. Allow to naturally release for 15 minutes.
When pot is done, remove bay leaf from pot. Ladle filling into ramekins. Place puff pastry on top of ramekins. Brush with egg wash.
Bake in 400 degree oven, or Instant Pot Omni for 10 minutes or until crust is golden brown.